Hi all, I have a very basic doubt -- but still, I am a newby!
My question is about referring to the previous row: in a sample as the following... ID X1 X2 1 A 12 2 A 6 3 A 10 1 B 17 2 B 19 1 C 22 1 D 13 2 D 19 3 D 21 ... I would like to create a dummy variable equal to 1 whenever the value of ID of the current row is lower or equal than the value of ID of the previous row -- check the new vector X3 I'd like to obtain: ID X1 X2 X3 1 A 12 0 2 A 6 0 3 A 10 0 1 B 17 1 2 B 19 0 1 C 22 1 1 D 13 1 2 D 19 0 3 D 21 0 I have searched a lot without finding a decent and working solution. I suppose it is just some basic matter of indexing language, something like X3<- as.numeric ( ID[n] <= ID[n-1]) but it is not so simple! thanks! Paolo ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
